JPS59378B2 - Adhesion method between polyolefins and metals - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method of adhering polyolefins to metals.

Polyolefin such as polyethylene is a non-polar crystalline resin and is an extremely stable resin that does not dissolve in ordinary chemicals or solvents and has good chemical and solvent resistance.

For this reason, it has been extremely difficult to bond polyolefins to other materials, such as metals. Conventionally, for such bonding of polyolefin and metal, for example, the polyolefin surface must first be pretreated (e.g., hot air or flame treatment, ozone gas treatment, corona discharge treatment, radiation treatment, thermoelectric potassium chromate-sulfuric acid mixture treatment, etc.). Yoshi,
A known method is to perform surface oxidation to form a polar group such as a carbonyl group, and then bond with an epoxy resin, polyurethane resin, or the like. However, with this method,
It has not been put into practical use because the pretreatment operation is complicated, the workability is poor, the cost is high, and the adhesive strength is highly uneven. Furthermore, such pretreatment methods can only be applied to sheet-like polyolefin materials, and cannot be applied to other forms, such as powders. For this reason, many attempts have been made to improve the adhesion to metals by modifying polyolefins or by copolymerizing olefins with vinyl monomers having other polar groups. A typical example is when a polyolefin polymer made by copolymerizing ethylene and acrylic acid is used, and the adhesive strength with metal is improved as is well known.
However, conventional laminates of modified polyolefins and metals, such as the above-mentioned polymers, do not have sufficient adhesion properties, including corrosion resistance, and easily peel off when brought into contact with seawater, making them impractical. It was scarce. Adhesion is in this state, but due to its other excellent properties, polyethylene powder can be used by fluid dipping method etc.
It is often used for lining wire mesh shelves for refrigerators, etc., and when lining such thin metal rods, due to the shrinkage of polyethylene, it is practically useful without using adhesive between the metal rod and the metal rod. be. However, in recent years, polyolefins with excellent chemical resistance have been used for lining the inner and outer surfaces of steel pipes, and at the same time, there is a need to provide excellent corrosion resistance, so useful adhesives, especially those that do not require the above-mentioned surface oxidation pretreatment, are being used. The emergence of adhesives has been strongly desired. The inventors of the present invention have carried out extensive research to provide an adhesive that satisfies such demands. As a result, the adhesive has the general formula NCH2OR (wherein R represents a hydrogen atom or an alkyl group).

] or N-alkoxymethylamino group represented by
Using a thermosetting compound having a methylolamino group,
We discovered that by combining this with a polyolefin polymer having a specific functional group, we could obtain a laminate of polyolefins and metals that not only had high adhesive strength but also had excellent water resistance and salt water resistance. The invention was completed. That is, the present invention provides the general formula>NCH2OR [wherein,
R represents a hydrogen atom or an alkyl group.

] or N.alkoxymethylamino group or N.
An adhesive layer formed on a metal by heating and curing a thermosetting adhesive having a methylolamino group is interposed, and the metal has at least one functional group selected from a hydroxyl group and a hydrolyzable group in the molecule. The present invention relates to a method for bonding polyolefins and metal, which comprises thermally bonding a polyolefin polymer or a mixture of the polyolefin polymer and another polyolefin. The polyolefin polymer having at least one functional group selected from a hydroxyl group and a hydrolyzable group in the molecule used in the present invention includes:
The following are exemplified, and their manufacturing methods are conventionally known.

(1) So-called normal polyolefins (e.g. low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, poly 1-butene, poly 4-methyl-
1-benzene, ethylene-propylene copolymer, etc.),
In addition, polyolefins copolymerized with polar vinyl monomers (e.g., ethylene-acrylic acid ester copolymers, ethylene-monovinyl acetate copolymers, etc.) are combined with hydroxyl group-containing monomers (e.g., vinyl alcohol, 3-buten-1-ol, etc.).
10-undecen-1-ol, β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, etc.), (2) copolymerization of the above-mentioned olefin monomer for the usual polyolefin and the above-mentioned hydroxyl group-containing monomer (3) A polyolefin having a hydrolyzable group, such as the above-mentioned ethylene-acrylic acid ester copolymer or ethylene monovinyl acetate copolymer, or a saponified product thereof.

In the present invention, the above-mentioned polyolefin polymers may be used alone or in combination with two or more thereof, or may be used in combination with the above-mentioned ordinary polyolefins.

It is also possible to add fillers and additives such as coloring pigments, extender pigments, and antirust pigments, if necessary. These polyolefins can be used in an appropriate form such as a sheet, film, or powder. The adhesive used in the present invention has the general formula〉NCH
It is a thermosetting compound or mixture having an N-alkoxymethylamino group or an N-methylolamino group represented by 2OR.

Specifically, so-called amino resins such as melamine resin, benzoguanamine resin, and urea resin, or N-methylolacrylamide monomer (CH2=CH-CONH-
Examples include acrylic resins containing CH2OH). In the present invention, the use of other resins that react with the above-mentioned N-alkoxymethylamino groups or N-methylolamino groups is more effective in terms of improving the practicality of the resulting adhesive laminate. . Amino resins, including melamine resins, are generally thermosetting, but while their cured films have excellent corrosion resistance, they have the disadvantage of being hard and brittle. Usually, other resins having functional groups capable of reacting with N-methylolamino groups are used in combination to compensate for the drawbacks. Even if the above-mentioned resin is used alone in accordance with the present invention, its adhesion and anti-corrosion properties can sufficiently achieve the objectives, but it is necessary to perform so-called post-processing in which the resulting adhesive laminate is bent, extruded, etc. In some cases, the processability of laminates is poor due to the sticky nature of the adhesive, which may pose a practical problem, so the use of other resins in combination is mainly used as a means to improve this processability. preferable. Other resins that can be used in combination include those having functional groups that can react with N-alkoxymethylamino groups or N-methylolamino groups, such as epoxy resins, polyester resins, acrylic resins, and alkyd resins. These resins that can be used in combination do not contribute to the adhesion of the above-mentioned polyolefins used in the present invention, so if their amount is increased, the adhesive strength of the laminate will decrease, so they should be used in as small an amount as possible. is desirable, and usually the above N-alkoxymethylamino group or N
- 90 (: f
) (Weight section, same below) Used in the following amounts. An adhesive mainly composed of a thermosetting compound or a mixture having an N-alkoxymethylamino group or an N-methylolamino group has a uniform 5 to 20 μm thickness in any state.
It is sufficient to form a film, but it is usually easier to use one dissolved in a solvent.

If necessary, fillers and additives such as coloring pigments, extender pigments, and antirust pigments may be added. The metals targeted by the present invention include commonly used metal materials such as aluminum, copper, zinc, nickel, iron, tin, stainless steel, brass, tinplate, and galvanized iron in plate shapes and other appropriate shapes.
Not restricted by material type.

The metal surface only needs to be clean and free from oil droplets, water droplets, or dust particles.
Sandblasting or chemical conversion treatment such as zinc phosphate is more effective in light of the purpose of the present invention. In the present invention, the adhesive is applied to a metal surface by a conventional method,
A uniform adhesive layer is formed by heating and curing at 60 to 250°C for 5 to 60 minutes, and then the above-mentioned polyolefin polymer or a mixture with ordinary polio V fin is adhered to the adhesive surface by a conventional method. .

For example, in the case of film-like polyolefins, 80
~5~100k9/c at ~200℃: 20~ at Rll2
It is sufficient to press and heat for 600 seconds. In the case of a powder, it can be electrostatically coated for 5 to 6 hours at 120 to 220°C.
It is sufficient to heat and melt for 0 minutes. In this way, a polyolefin-metal bonded body having sufficient adhesive strength and corrosion resistance can be obtained. The present invention, which has the above configuration, can be used to bond polyolefins and metals, which has been considered difficult in the past.
Adhesion methods such as extrusion lining and powder lining can be applied to sheet or film shapes without the need for complicated surface oxidation treatment of polyolefins, and without any restrictions on the shape of polyolefins. It is an adhesive method that can provide practical adhesive strength and excellent corrosion resistance.

Moreover, by combining the adhesive of the present invention with the powder lining method, it is not only possible to line complex-shaped metals with polyolefins, but also because polyolefin lining materials for metals have excellent corrosion resistance. This makes it possible to use polyolefin linings in the corrosion protection field, where they have not been previously applied. Next, the present invention will be specifically explained with reference to Examples and Comparative Examples.

Note that "parts" and "%" in the example sentences mean "parts by weight" and "% by weight." Example 1 Melamine resin (
Manufactured by Dainippon Ink Co., Ltd. Product name: “Super Betsucomin J-82”
0''] and 80 parts of polyester resin (polycondensate of terephthalic acid, neopentyl glycol and trimethylolpropane, acid value 6, hydroxyl value 400-600, molecular weight approximately 2200), xylol/methyl isobutyl ketone/butyl cellosolve/ Butanol (weight ratio: 2/1
/1/1) Prepare an adhesive by dissolving in 400 parts of mixed solvent.

Next, apply the above adhesive to an iron plate (0.8 x 70 x 150 m1!
) and heat cured at 200°C for 20 minutes to form an adhesive layer, and then coated with adhesion-imparting polyolefin powder (trade name: "Dyumilan D-159" manufactured by Mitsui Polychemicals Co., Ltd., ethylene monovinyl acetate copolymer 90). (:f) Hydrolyzate (saponified 90% of acetate in the molecule), M=
15) was applied electrostatically and heated and melted at 180°C for 20 minutes to form a 200μ thick polio V fin JC film.

In this way, a laminate of polyolefin and iron plate is obtained. A part of the film of the laminate is forcibly peeled off, the peeled part is held, and the 180 peel strength (adhesion strength) with a steel surface is measured using a Tensilon.

Further, a cut extending to the iron surface is made in the film of the laminate, and the cut is immersed in 3(f) saline solution at 60° C. for 30 days, and the peeling distance of the film from the cut portion is measured. The results of these measurements are shown in Table 1. Comparative Example 1 In Example 1, adhesion-imparting polyolefin powder C'
Low density polyethylene powder (product name: Frozen FG-801 manufactured by Steel Chemical Co., Ltd.) was used instead of
], MI=20) was used under the same conditions to obtain a laminate, and then the adhesive strength and peel distance of the laminate were measured.

The results are shown in Table 1. Comparative Example 2 A laminate is obtained under the same conditions as in Example 1 without forming an adhesive layer on the iron plate, and then the adhesive strength and peel distance of the laminate are measured.

The results are shown in Table 1. Example 2 In Example 1, adhesion-imparting polyolefin powder ("
Adhesion-imparting polio V-fin powder (trade name: "Dyumilan D-157" manufactured by Mitsui Polychemical Co., Ltd., 70% ethylene monovinyl acetate copolymer) instead of "Dyumilan D-159")
A laminate is obtained under the same conditions except that a hydrolyzate (MI=15) is used, and then the adhesive strength and peel distance of the laminate are measured.

The results are shown in Table 1. Example 3 Adhesion-imparting polyolefin powder (product name: Mitsui Polychemical Co., Ltd.
A film with a thickness of 200μ made from "Evaflex 150", ethylene monovinyl acetate copolymer, MI = 15) by the inflation film molding method was pressed and melted at 160°C for 1 minute at about 10k9/CTL2, and the polyolefin and iron plate were melted. A laminate is obtained.

The adhesive strength} and peel distance of the laminate were measured in the same manner as in Example 1, and the results are shown in Table 1. Example 4 In addition to Example 1, benzoguanamine resin (trade name "Super Betsukamine G-821" manufactured by Dainippon Ink Co., Ltd.)15
and 85 parts of an acrylic resin (trade name "Dyanal HR-124" manufactured by Mitsubishi Rayon Co., Ltd.) were dissolved in 200 parts of a xylol/methyl isobutyl ketone/butanol (weight ratio: 2/1/1) mixed solvent. A laminate was obtained under the same conditions except that an adhesive was used, and then the adhesive strength and peel distance of the laminate were measured.

The results are shown in Table 1. Example 5 In Example 1, a self-crosslinking acrylic resin having an N-methylolamino group (styrene-butyl acrylate-
20 parts of isobutyl acrylate-N-methylol acrylamide copolymer) was mixed with xylol/methyl isobutyl ketone/butyl cellosolve/butanol (weight ratio: 2/1).
/1/0,5) A laminate is obtained under the same conditions except that an adhesive prepared by dissolving in 80 parts of a mixed solvent is used, and then the adhesive strength and peel distance of the laminate are measured.

The results are shown in Table 1. Example 6 In Example 1, 20 parts of urea resin (trade name "Betsukamine P-138" manufactured by Dainippon Ink Co., Ltd.) and 20 parts of epoxy resin (trade name "Epotote 014" manufactured by Tobu Kasei Co., Ltd., epoxy equivalent 850 to 900, molecular weight approx. 1700) and 80 parts of xylol/methyl isobutyl ketone/butanol (weight ratio:
2/1/1) A laminate is obtained under the same conditions except that an adhesive prepared by dissolving in 400 parts of a mixed solvent is used, and then the adhesive strength and peel distance of the laminate are measured.

The results are shown in Table 1. Comparative Example 3 In addition to Example 1, 100 parts of an epoxy resin (trade name "Epotote 011" manufactured by Tobu Kasei Co., Ltd., epoxy equivalent weight 450, molecular weight approximately 900) and a polyamide curing agent (trade name "Sunmide X-" manufactured by Sanwa Kagaku Co., Ltd.) were added. The same conditions were used, except that an adhesive prepared by dissolving 40 parts of ``2700'') in 60 parts of a mixed solvent of xylol/methyl isobutyl ketone/butyl cellosolve/butanol (weight ratio: 2/1/1/1) was used. A laminate is obtained, and then the adhesive strength and peel distance of the laminate are measured.

Claims (1)

[Claims] 1 General formula>NCH_2OR [wherein R represents a hydrogen atom or an alkyl group]. ] or N-alkoxymethylamino group represented by
At least one functional group selected from a hydroxyl group 2 and a hydrolyzable group is added to the metal through an adhesive layer formed on the metal by heating and curing a thermosetting adhesive having a methylolamino group. 1. A method for adhering polyolefins and metal, the method comprising thermally adhering a polyolefin polymer having the same or a mixture of the polyolefin polymer and another polyolefin.